Regulation of the quality of surface run-off water entering urban drainage systems is currently a high priority for many local, state and federal environmental agencies.
Surface run-off picks up chemicals, hydrocarbons, animal feces, and other pollutants. Such contaminated run-off has heretofore been allowed to flow unchecked into nearby storm drains. Contaminated water arises from: rain and snow, residential and commercial car washing, residential hose down, garage/shop concrete pad/floor washing, pressure washer cleaning, concrete sawing and drilling, aggregate washing, boatyard hull cleaning, parking lot surface cleaning and many other sources.
Also, drain cleaners often generate spilled water which may cause flood damage and pollution and require extensive clean up. Emergency response crews encounter flooding from broken pipes, sprinklers, failed valves, etc. Oftentimes, the flooding must be contained or diverted immediately to avert danger.
Sewage treatment plants have a limited processing capacity which, typically, is fully utilized if not over utilized. Therefore, as suggested above, strict controls on the generation of polluted surface water and other fluid contaminants which might reach sewers or storm drains are being widely implemented.
One approach to the resolution of this problem is to contain the polluting liquid and then remove it from the surface. Containment methods now used in emergency and non-emergency situations usually involve earthen berms, sandbags or absorbent materials. Constructing sand bag berms is a very time consuming and labor intensive process. Material to construct the berm has to be delivered to the emergency site. Bags are filled one at a time, and hundreds or thousands may be needed. Because time is of the essence in emergency situations, many people are required. Adsorbents have a limited storage capacity. Once used they must be disposed of. Also, none of the above methods prevents seepage completely.
Another method of resolving the problem is to block storm drain grates, thus preventing contaminated water from passing through them. The water is then allowed to stand until it either evaporates or is removed by a cleanup crew (usually with a vacuum truck).
Yet another method is to plug the drainage ports of catch basins and allow water to enter the basin. Later the contaminated water is pumped out and properly discharged.
In some situations waste water generators install expensive water reclamation systems. Unless the user is assured of being at that location over the long term, this approach may not be economical. This is because this method requires installation of a permanent, expensive wash pad and drain; this method is particularly disadvantageous when the user occupies a leased facility and must leave this investment in place when the facility is abandoned.
The above methods are very expensive and/or inconvenient. These difficulties force small quantity pollution generators to ignore discharge regulations. They'd rather risk getting caught and fined then go to the trouble and expense of pollution control.
Furthermore, as indicated above, complete containment of the polluting fluid is a serious problem. This is particularly true of fluid lying on a textured surface.
Examples of textured surfaces commonly polluted with fluid contaminants include: asphalt road pavements, parking lots, and driveways; washed aggregate; driveways; concrete pavements, sidewalks, waterways, vaults, culverts, parking garages, driveways, hard packed gravel staging pads, remote roads, parking lots, and industrial yards.
Containing liquids flowing on textured surfaces is difficult because of the large force required to compress a blocking material into the cracks and openings of the textured material to the extent necessary to prevent seeping. Even then, it is often difficult to produce a watertight seal; and any device relying on weight to generate a tight seal is too heavy and difficult to expeditiously handle.
The foregoing and other problems are resolved by the novel assemblies for containing and evacuating fluids disclosed in U.S. patent application No. 07/725,635, which is the parent application of the present application. In general, systems such as those disclosed in the parent application include a boom designed to act as a barrier to the offending fluid. This boom has a casing which defines a vacuum chamber and a compressible gasket at a lower open end of the casing. When the casing-defined chamber is evacuated, the pressure differential on the casing forces it toward the surface on which the boom is placed, compressing the gasket. This forces the gasket into intimate contact with the surface, locking the boom in place and producing a tight seal between the boom and the surface. This keeps the liquid from seeping or otherwise escaping past the boom.
The gasket may be fabricated from an impervious, compressible material in which case the boom serves simply as a barrier to migration of the offending liquid. Alternatively, a gasket with communicating open pores may be employed. Additionally, a fluid level-controlled pump may be provided to keep the reservoir from overflowing. Further, a variety of gasket materials, configurations, and mounting schemes can be employed.
One of the important advantages of fluid containment systems as described in the parent application No. 07/725,635 is that heavy weights are not required to generate a tight and effective seal between the boom and the surface on which it is employed. This is true even if the surface is a textured one as exemplified above or a textured surface of the character associated with ceramic and other tiles, decorative floor coverings, carpets, and the concrete floors of garages and basements.
However, in some cases the boom disclosed by the parent application No. 07/725,635 is insufficiently flexible to accommodate: (a) the surface on which the liquid to be contained is flowing or accumulating; and/or (b) the character of the accumulation or flow of this liquid.
For example, should the offending liquid be flowing or accumulating on a severely undulating surface, the boom may not be flexible enough to conform to such a surface; gaps through which liquid may escape may occur under the boom at points above low spots on the surface between two closely adjacent high spots thereon. Additionally, these gaps allow air to enter the plenum, reducing overall efficiency and performance of the system.
Additionally, if the offending liquid is flowing in a narrow stream, it may be desirable to place the boom on the surface in a U-shaped configuration so that the liquid flows into the open end of the "U." In this case, the boom should be capable of accommodating a tight radius at the bottom, closed end of the "U" and have long, straight, side walls for forming the sides of the "U".
Alternatively, if the offending liquid is accumulating in a pool, it may be desirable to form the boom in a circle that completely surrounds the pool.
Another potential problem with the device taught by the parent application No. 07/725,635 is the location and orientation of the fittings through which liquid is evacuated from the boom plenum. The Applicant has discovered that placing these fittings as disclosed in the parent application allows liquid to accumulate within the boom plenum. When the liquid level reaches the bottom end of the fitting, liquid is sucked into the line leading to the reservoir. This causes the vacuum system to "burp", interrupting the vacuum within the boom plenum and thereby allowing liquid trapped in the plenum to seep out from between the boom and the surface on which it sits. This arrangement of the fittings also inefficiently conveys air leaving the boom plenum into the vacuum hose.
A further difficulty is that the boom disclosed in the parent application is insufficiently flexible if it must be placed at odd angles to capture or gather liquids, to accommodate an obstacle in the boom's path, or to capture liquid flowing in all directions such as on a flat surface.
Finally, it would be desirable if the span of the boom could be increased or decreased as appropriate for a given situation. For example, a boom of a certain span might be too large to evacuate liquid from a first room and too small effectively to evacuate liquid from a second room.